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Stability issue resolved
The stability issue with our iSCSI storage server that required us to postpone the system update has been resolved. It was caused by an incompatibility between the iSCSI server software and Linux 2.6.39. We resolved the issue by selecting 2.6.38 as the new kernel version for this update instead.
Order of events
With the system update next week the order of the next events will be:
This week:
- Announcement of general resource group maintenance settings by email
- Announcement of specific maintenance windows for every VM by email
Next week:
- Monday morning: update of infrastructure machines, watch for any deviations, fix of last minute-bugs if necessary, no downtime expected. If anything goes wrong this will be our chance to cancel any customer-affecting updates.
- Monday evening: update of a representative set of machines including selected customer VMs.
- Tuesday evening: initiate update on 20% of all machines
- Wednesday evening: initiate update on 30% of all machines
- Thursday evening: initiate update on the remaining machines
- Saturday: reboot of all VM host machines
During the week we have also scheduled an early-morning and late-night shift of our support personnel that will keep an eye on the services during and after the system update and fix any issues arising or contact you in case of issues that we can not fix for you.
Please note that all VMs will be rebooted twice: once during their regular maintenance window to activate the new kernel and a second time on Saturday without a regular maintenance window due to the necessary restart of the KVM hosts.
Automatic maintenance scheduling
With the growing number of machines that we support in gocept.net and the ultimate goal of providing a transparent, flexible yet automated service we took your feedback from the last months and chose to implement a better mechanism to support maintenance activities than the existing "automatic reboot" scheduler that only paid attention to system load and did not communicate.
The new implementation allows any machine to queue "maintenance activities" like memory resizes, changes on the number of CPUs, kernel updates, or larger system updates. Depending on the settings of the resource group our central directory is then able to automatically schedule a window for those activities and notify the machine of the time that the activity should be performed at.
Every resource group now has settings for:
- your technical contact email addresses
- your preferred timezone
- a daily interval that can be used for scheduling regular maintenance automatically
- what period you need to be informed before any maintenance activity.
Every machine has an additional setting that controls whether this machine is allowed to automatically schedule new maintenance windows.
To introduce this feature you will first receive individual emails for each resource group that display the values we used to initialize this for you. After preparing the full roll-out schedule for next week, you will then receive emails about the windows that we schedule for each individual machine.
More swap for small VMs
All VMs now get at least 1GB of swap space. This will help smaller VMs that need to run the same system administration tools that stay in memory but get swapped out by the kernel regularly. This way you can make more effective use of the memory in smaller VMs without our system management getting in your way.
Multi-core VMs
Due to popular demand we are now introducing multi-core VMs: you can choose to run up to 12 cores per virtual machine.
However, we still recommend to use the multi-core feature wisely: dividing up your application over multiple smaller VMs has positive side effects like load-balancing and higher fault tolerance on the infrastructure level and it ultimately scales to many more cores. It also usually means the setup of each individual VM is much simpler, more testable, and thus more maintainable. Also remember: the operating system for VMs is still at 32-bit so you're limited to a total of 4GB of memory in the VM and 3GB per process.
We will charge 25 EUR per additional core per month.
Software updates
The package catalog has been updated and now includes, amongst others, Linux 2.6.38, Python 2.5.4, 2.6.6, 2.7.1 and 3.1.3. A more detailed list of package updates is shown in our official ChangeLog.
To perform the package updates faster then in the past we have now improved our binary host system for pre-compiling the packages in our development environment and then directly pushing them onto the data center mirrors. As we use a well-adjusted check-summing mechanism to ensure binary compatibility this ensures that the packages are already in the data center when the machines start updating.
CPU visibility
Do you wonder which CPU actually powers your VM? Running `uname -a` now shows the actual physical CPU identification instead of the generic `qemu virtual CPU`.
As we run a mixed environment that constantly get updated you might see different CPU numbers on different machines. If you think you could benefit from a better CPU then drop us a note and we'll see whether we have some free space on a system with more power.
New configuration schema for PostgreSQL 9
The PostgreSQL configuration schema has been adjusted by Gentoo to be more Unix-like and thus locate the configuration files in /etc/postgresql-9.0 instead of /srv/postgresql/9.0/data.
More documentation
In case you haven't noticed: we have also silently been updating our gocept.net documentation to give a better overview of our architecture, help you get started and explain the typical tasks in our environment.
We're very excited putting those improvements into good use and hope that they will further improve your experience of our hosting services.
Your gocept.net system administrators